Real time data carrying multimedia applications, such as voice or video, is transmitted over the Internet using the Real Time Protocol (RTP). VoIP (Voice over IP) is becoming increasingly popular to the consternation of law enforcement agencies that have legitimate needs to tap into calls for law enforcement purposes. For regulatory law enforcement reasons, a call between two parties may have been authorized, through proper law enforcement procedure, to be monitored by selected law enforcement agencies.
A conventional telephone conversation involves the establishment of a physical connection between the calling and called parties. While this physical connection might merely be a channel within a time division multiplexed system, it nevertheless is dedicated to the parties during the call and this makes it relatively easy for the law enforcement agencies to tap into the call. On the other hand, VoIP, for example, which involves the use of packets individually routed between the parties, is much more difficult to intercept, especially without alerting the parties to the presence of the intercept. Typically attempts at processing the packets to extract the data will introduce latency that is observed by the parties as unusual delay, thus alerting them to the possibility of an intercept. Similar problems arise with other types of multimedia streams.
An object of the invention is to provide a method and apparatus for intercepting real time packet traffic that has a low probability of alerting the participants to the intercept.